Fluctuating Progesterone

Has anyone had a similar situation and still a healthy pregnancy? I have a 20 month old son born December 2017. I had two losses in 2018. Now 8w3d pregnant and have been on progesterone since 4w. I just went yesterday for an ultrasound and blood work and all was good on the ultrasound. Baby was right size and HR was 162. My progesterone levels are fluctuating and I’m a nervous wreck.

4 weeks - 17

5 weeks - 22

6 weeks - 19

8 weeks - 14

My doctor called today and upped my progesterone dosage from 200mg daily to 400mg daily and I go next week for another blood draw.